850 Running rich

[Ken Oh]

I've rebuilt the carb ( float is good ), compression is per spec., adjusted valves, set timing, ign. parts are good. Nothing has helped.
Work it for an hour or so and the plugs are so sooted up she starts popping and backfiring and I have to clean the plugs again.

When I set the timing I had to turn the distributor quite a bit to get it to 5 deg. I don't know where it was at before, as I only cleaned the 5 deg. mark.

Also it is not charging. I use it for an hour, then clean the plugs and charge the bat. Because of this am I getting a weaker spark?

Don't have any way to check the coil.

Any suggestions?

Thank you.

 

[old]

Well if its running rich what happens if you close up the main jet some. If you can close it up all the way and it will still run that means you missed something in the carb. Main jet starting point is 1.5 turn out from bottom but as I said if you can close it all the way and it will still run the carb is still clogged up
Hobby farm

 

[Ken Oh]

Yes. Closing the main needle will make it start missing and it will quit running if the needle is closed.

 

[old]

Then its just a matter of adjusting the main jet correctly and also making sure your oil bath air cleaner is clean and not clogged up.
Hobby farm

 

[SparepartsTN]

Ken Oh,

You mentioned turning the distributor quite a bit to get to 5 degrees of timing. My books call for 26 degrees for 55-57; and 24 degrees of timing for 1958 and later. When I first got my 861/4000 it was not charging but would run for several days before it had to be charged again, since I rebuilt the generator I haven"t had that problem, but a weak battery will reduce your spark when it gets weak enough.

Warren

 

[Ken Oh]

sparepartsTN,
Thanks for the reply. My Ford owners manual calls for 5 deg. BTC for the 800 series, and 8 deg. BTC for the 600 series. 26 deg. sounds pretty high to me.

Old,
Went out and tore the carb apart. Very clean inside since it was soaked in carb cleaner when I rebuilt it. Any way I ran wires through all passages, sprayed cleaner through them, and blew them out with 110 psi. air. Checked the floats for leaks and adjustment. Put it back on and still have the problem. BUT, at wide open throttle I CAN close the main needle and it still runs, albeit badly. Unless there is a hole or passage that I can't see I don't know what else to do. These carbs are pretty simple compared to all the automotive carbs I've rebuilt.
Any other ideas?

Ken

 

[old]

BTDT and even with them being simple they can be hard to get as clean as they need to be. I have opened up carbs soaked them and did the wire thing and still have the same problems I started with. All it takes is one small pice of dirt/rust that you miss and you will have problems. Also if the bottom of the carb bowl is ruff some times that will cause problems. Also this may sound funny but you could also have a bad condenser. I had one not long ago 6that I believed was a crab problem and it would run well for 10-15 minutes act like it was running out of gas one time then the next act like it was running rich and it ended up being a bad condenser

 

[Jerry/MT]

Make sure that the float is set correctly. If you shut the main jet off and it"s getting fuel and the engine is running above idle rpm I think your float level is set too high.

 

[NWMO 901 SOS]

I agree with you on the timing Ed. My manual gives

5 degrees BTDC @ 450-475 rpm
14.5-16.5 degrees BTDC @ 1200 rpm
26-28 degrees BTDC @ 2200-2400 rpm

I'm assuming you timed it at low idle. I will say some tractors don't like to idle that slowly and that could effect things some. 2200-2400 rpms would be screaming.

Best of luck

Chris

 

[duck64759]

Hey Old,you thought you had a crab problem. I gotta kick outta that one!